The National Space Transportation System external tank is a sacrificial structure used for approximately eight and one-half minutes during each space launch. This external tank provides liquid oxygen and liquid hydrogen to the orbiters main engines. The external tank is designed to carry sufficient propellant to place the external tank (attached to the orbiter) into low Earth orbit. Currently, the external tanks are jettisoned just prior to low Earth orbit insertion, and subsequently tumble and break up in the atmosphere before falling over open seas. The external tank consists of two pressure vessels, an oxygen tank and a hydrogen tank, joined by a cylindrical intertank structure.
In U.S. Pat. No. 4,807,833 (Pori), the configuring of a space vehicle fuel cell or tank in order to provide modular structural building components for a space station is disclosed. The configuring of the fuel cell includes the modifying of existing intertank structure to provide two concentric fuel storage tanks.
Other patents of general interest include: U.S. Pat. No. 3,866,863 (von Pragenau) which discloses a space vehicle using an external fuel cell; U.S. Pat. No. 4,132,373 (Lang) which discloses a manned space flight body comprising a cylindrical shell; and U.S. Pat. No. 4,122,991 (Johnston, et al.) which discloses a pre-punched ribbon structure which is formed around an external fuel cell.